Crystallization Induced Asymmetric Transformation: Synthesis of D-p-Hydroxyphenylglycine

Abstract D-p-hydroxyphenylglycine (D-HPG) is prepared from racemic HPG via salicylaldehyde mediated resolution-racemization of the corresponding D-3-bromocamphor-8-sulfonate salt in acetic acid. After slurry purification to improve the de to >99.9%, the crystallized salt is neutralized to produce D-HPG in 92% overall yield and 99.9% ee.